Comparing autism and OCD within a Compulsive and Repetitive Trait framework : do Free Will beliefs predict clinical symptoms?

Chegwin, Samuel Thomas

September 2018

Thesis or dissertation

© 2018 Samuel Thomas Chegwin. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.

Background Although a range of evidence suggests links between OCD and autism, there remains a lack of clarity on how symptoms may be related between these disorders. Repetitive traits are key components in both OCD and autism. Understanding the functions and origins of these traits is crucial. Repetitive traits in OCD are ego-dystonic, therefore related to distress. However, the nature of repetitive traits in autism is less clear. Historically, they were assumed to be ego-syntonic, therefore opposed to distress. However, recent evidence indicates ego-dystonic and
ego-syntonic properties of repetitive traits may be demonstrated in autism. The main aim in the present thesis, therefore, is to investigate the relationship between mood and repetitive traits in autism and OCD. These findings would indicate whether disorders such as autism and OCD may be better understood within a Compulsive and Repetitive Trait (CaRT) framework. A pilot investigation is also put forward to investigate whether free will beliefs – an unstudied concept in autism research – may offer further insight into a CaRT framework.

A cross-sectional questionnaire method compared adults with autism, OCD and neurotypical peers on OCD traits, Repetitive Behaviours and Free Will beliefs.

Repetitive Behaviours were comparable in number and frequency between the OCD and autism groups, with higher positive mood in the autism group. OCD traits were highest in number and severity for the OCD group, although significantly higher in the autism compared to the control group. Groups did not differ on the presence of CaRTs due to social context. Strong correlations were identified between OCD traits and Repetitive Behaviours, despite no correlations being found between mood associated with these traits. No differences in free will beliefs were demonstrated between the groups, although there was some indication of the significance of Scientific Determinism beliefs in autism.

The research presented appears to support the usefulness of a CaRT framework to compare symptomology between autism and OCD. Mood appears to be an important factor in distinguishing between CaRTs. Comparable free will scores indicate clinical behaviours (CaRTs) may be relatively independent of free will beliefs. Limitations are discussed, which may have masked stronger evidence, such as the unrepresentative nature of the samples.

Department of Psychology, The University of Hull
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